Everything was fine, but trying to find some info on the possible culprit for the battery standby drain, I found somewhere that it could be a problem with the Russian region UAMF7 rom. So, I downloaded, and installed the Indian DDUAMJ2 rom, rooting using arco68's files from http://forum.xda-developers.com/show....php?t=2494435, but didn't have wifi, so I then flashed MJNazari's kernel from http://forum.xda-developers.com/show....php?t=2431953.
Now everything's fine, wifi works, still don't know about the battery drain, but information in the "About device" worries me.
The build number is fine, JDQ39.I9192DDUAMJ2, but the Baseband version is still showing I9192XXUAMF7 !?
Is this normal, and have I messed something up somewhere?

Modem did not upgrade
Either flash whole rom AGAIN or only flash modem
This happens when u have "Custom" status in download mode.
U can extract modem from stock MJ2 rom tar and md5 it and reflash it
Here is the modem i extracted from MJ2 flash it with Odin CP option
I9192DDUAMJ2_Modem.tar.md5 37.2 MBhttps://mega.co.nz/#!5Q9kSaDQ!QrKvmz...ikoR_5CMfdEC2g

Modem did not upgrade
Either flash whole rom AGAIN or only flash modem
This happens when u have "Custom" status in download mode.
U can extract modem from stock MJ2 rom tar and md5 it and reflash it
Here is the modem i extracted from MJ2 flash it with Odin CP option
I9192DDUAMJ2_Modem.tar.md5 37.2 MBhttps://mega.co.nz/#!5Q9kSaDQ!QrKvmz...ikoR_5CMfdEC2g

Thank you very much!

I had tried flashing the entire ROM twice, even did a factory reset, wiping the whole lot of everything I had on the device

BTW, on a technical note, where does that "Custom" status come from? Rootkit? Kernel?

I had tried flashing the entire ROM twice, even did a factory reset, wiping the whole lot of everything I had on the device

BTW, on a technical note, where does that "Custom" status come from? Rootkit? Kernel?

Well, depends
For example if u take a stock rom from sammobile , unpack it and delete bootloader stuff when u`ll flash it status will go "custom" even if u did not modify other stuff
If u flash a custom kernel / recovery status will go custom
If u delete some "bloat" status will become custom
Many things will trigger that status
Good part is , u can come back to official if u flash a stock unmodified rom from sammobile and factory reset your phone after
Take care, sometimes u must flash it twice or more because modem does not get flashed
Btw, u are lucky u still don`t have Knox bootloader do not flash a stock rom from sammobile that ends with MK4 MK5 ML1 ML2 ML4 NA2 etc without modifying and deleting Knox bootloader

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